Cant activate iphone7 due to update error

I got a used iphone 7 recently, I had to due a factory reset on it because previous owner didnt remember their passcode. When I did this the phone reset perfectly fine into its factory mode but now when I try to activate it says update required. Ive tried to bring the recovery screen up but it wont come up, ive held the buttons for over a minute. Its said that certain iphone 7 models have problems like this. I have the model A1660.